MAYS LANDING, N.J.- Her story: She was bored in her new boyfriend's Atlantic City condo and persuaded him to take her out to a nearby casino, where they saw a gleaming new Lincoln SUV and carjacked the driver. Her boyfriend stabbed the owner to death before torching the vehicle to cover up their crimes.![endif][/htmlcomment]>

His story: His girlfriend was trying to collect a mysterious $500 debt from "some guy." Hours after she had promised to take him out to dinner and gambling, she showed up with a new SUV, saying she had "a problem" and needed to get rid of it. So he did what any guy with a hot young girlfriend would do by burning the car for her. But that's all he did.

Those two contradictory narratives played out in court Monday in the murder trial of Craig Arno, 46, of Atlantic City. He is accused of the carjacking and murder of Martin Caballero, a 47-year-old North Bergen man who was accosted in the parking garage of the Trump Taj Mahal Casino Resort on May 21, 2010, after dropping his family off at the main entrance. They were there to celebrate his daughter's birthday.

The girlfriend, Jessica Kisby, pleaded guilty to murder in February and will serve 30 years in prison before being released.

Kisby, 26, testified that she and Arno were driving near the Taj Mahal when they saw the Lincoln SUV and followed it into the casino garage.

"I assumed we were just gonna rob him, something stupid," she testified.

Much of Kisby's testimony was delivered in a matter-of-fact tone that at times was shocking in its nonchalance, particularly as she described the kidnapping and two-part knife assault that killed Caballero.

At times she laughed, smiled or fidgeted with her ponytail. She yawned several times. Other times she rested her elbow on the witness stand and rested the side of her head on it. Once, she reached her hands as far over her head as she could and appeared to be stretching.

Arno, in contrast, had a smirking quality to his testimony, proud of his steps to protect a woman more than 20 years younger than he was.

"Honestly, I'm a man," he said of his feelings about having a lover two decades his junior. "Any man who tells you it isn't a big deal is lying."

In Kisby's retelling of the crime, she said she walked up to Caballero, who was getting out of the vehicle, and tried to chat him up. Then, she said, Arno came up, pulled a gun from his waistband and forced Cabellero into the trunk of the car. They drove to a nearby bank, where she said, Arno tried to use Caballero's ATM card to withdraw money. But the victim had already reached his daily limit; the robbers would have to wait until after midnight to try again.

"He told me to get a knife out of the door" of the Toyota, Kisby testified. "It was like a boning knife. It was thin.

"We didn't really discuss exactly what was going to happen," she said. "He (Arno) just said he knew a place to go. We were going to kill him."

They drove to a rural area about 20 minutes west of Atlantic City. Asked if Caballero made any noise during the ride to his death, Kisby said she didn't know.

"I was busy messing with the radio," she said.

They parked on a dirt road, and looked each other in the eye before Arno started stabbing the victim. Kisby said she was waiting outside the car with a box cutter.

"The guy started kicking," she testified. "I started slicing at his legs to get him to stop. I started holding his legs because he was kicking so much."

And then, Arno's knife broke, she recalled. They had to stop the deadly assault, she said, and drive to Kisby's mother's house in Egg Harbor Township, about 15 minutes away, where she grabbed two knives and got back in the car, with Caballero bleeding in the trunk.

"We started it," she recalled. "Gotta finish it now."

They drove back to the same spot, she testified, and Arno went back to the trunk. Then Arno raised the knife, she said.

"I saw him making stabbing motions," Kisby said. "It was a lot. I can't count." More than 10, she said.

When Caballero was dead, Arno pulled the body out of the trunk and dragged it to some nearby bushes, she said, leaving it there.

Arno's story was vastly different.

He testified that Kisby left their condo on an errand to collect $500 from "some guy." He said he and Kisby were to meet on the Boardwalk near the Showboat Casino Hotel around 10:30 p.m., so that she could treat him to dinner and some gambling with the cash she'd be retrieving.

But instead, Arno testified, she told him she had trouble with the guy, and turned up hours later driving a new white Lincoln, obviously upset.

"I got a problem," she said, according to Arno. "You gotta help me. We gotta get rid of this car. Please, please, please!"

Arno said he felt protective of his young girlfriend and agreed to set it ablaze. In the process, he said, he seriously burned himself. But he maintained that was all he did, denying any role in Caballero's death or the carjacking.

He said he agreed to help her even though "the whole story is a little far-fetched, the story she's telling me."

Days later, he saw his face on a news report from a surveillance video. The only thing on his mind, he said, was "getting as far away from New Jersey as I possibly could."

They were arrested several days later at a cheap motel just outside Atlantic City - the same motel behind which the bodies of four Atlantic City prostitutes were found in 2006, killings that remain unsolved.